Delayed-action, hydrostaticallyoperated arming device



July 20, 1965 G. P. KALAF 3,195,460

DELAYED-ACTION, HYDROSTATICALLYOPERATED ARMING DEVICE Filed July 26, 1962 FIGJ.

INVENTOR. GEORGE P. KALAF' 44,-... 0. Maia? T'T ORNEYS.

United States Patent 3,195,46tl DELAYED-ACTHN, HYDRDSTATKCALLY- ARR ENG DEVKCE (George F. Metal, Roclrviile, Md, assignor to the United States of America as represented by the Secretary of the Navy Filed July 25, 1952, Ser. No. 212,751 55 Claims. (Q1. ran-1s (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to hydr ostatically operated devices, and more particularly to delayed action devices for arming mines in shallow water.

In the past, it has been the general practice to provide hydrostatically operated devices for arming both shallow and deep water mines. One of the most critical problems confronting designers of arming devices for shallow water mines has been compensation for the effect upon the hydrostat of variations in internal mine pressure. When a mine is laid in shallow water, the hydrostatic pressure available to actuate the hydrostat is quite small i.e., in the order of a few pounds per square inch. Consequently, variations in internal mine pressure due to temperature changes become significant for mines laid in shallow water.

Various techniques have been proposed to compensate for the effects of increased internal mine pressures upon the hydrostatically operated arming device. One prior art method provided an arming device having means for adjusting the spring bias of the hydrostat in accordance with the estimated temperature diiferential between the mine case at the time of sealing and the water temperature expected at the mine planting area. Another method provided a device which employed a spring biased evacuated bellows which acted upon the arming device to supplement the water pressure force in response to increased internal mine pressures. Although such devices have served the purpose, they have not proved entirely satisfactory under all conditions of service. For example, the former device involves an educated guess as to the water temperature at the planting area and precludes the use of the mine in waters having different temperatures without openin the mine and resetting the device. The latter device also involved complicated linlo ages which increased the possibility of failure.

The general purpose of this invention is to provide a shallow water arming device for a mine which embraces all the advantages of similarly employed prior art devices possesses none of the aforedescribed disadvantages. To attain this, the present invention contemplates a delayed action hydrostatically operated arming device embodying a unique structure whereby variations in internal mine pressure are precluded from having any substantial etfect upon the arming device in opposition to the sea water actuating pressure.

An object of the present invention is the provision of an improved hydrostatically operated device which will arm mines in shallow water.

Another object is to provide a hydrostatically operated arming device which is substantially unaffected by variations in internal mine pressure.

A further object of the invention is the provision of a hydrostatically operated arming device incorporating a delay feature which permits the safe withdrawal of the mine laying ship.

Still another object is to provide a hydrostatically operated mine arming device which will complete an explosive train, or close electrical circuits, or both.

3,11 $35 Add Patented July 20, 1965 Yet another object of the present invention is the provision or" a hydrostatically operated mine arming device for a shallow water mine wherein the ratio of the force applied by the ambient water to the force applied by the internal mine pressure is large whereby variations in internal mine pressure have a negligible effect upon the operation of the arming device.

With these and other objects in view, the present invention in the broadest aspect contemplates a bellows or other expansible chamber immersed in a viscous fluid and adapted to move an actuating rod upon expansion or contraction due to pressure exerted on the viscous fluid, and means on the actuating rod for arming the mine mounting the device. Means are provided for sealing off the interior of the bellows or expansible chamber from the internal mine pressure. Means are also provided for delaying the action of the device for a suitable period of time. Various refinements may include resilient means normally urging the bellows or expansible chamber to a safe position, means for locking the bel lows in this position to preclude premature arming, and means for limiting the extent of movement of the bellows and actuating rod.

Other objects, advantages and novel features of the invention will become readily apparent upon consideration or" the following detailed description when taken in conjunction with the accompanying drawing wherein:

PEG. 1 is a longitudinal section through a device embodying the principal features of the present invention and illustrates the relationship of the various parts when the device is in the safe or unarmed position; and

PEG. 2 is a View similar to FIG. 1 and illustrates the relative positions of the various parts in the armed position.

Referring now to the drawing, wherein like numerals of the reference designate like or corresponding parts throughout the several views, there is shown a housing it having an open end defined by a mounting flange lit and a closed end defined by a closure plug 12 threaded into the housing iii. A piston 14 is slidably disposed within the housing lit and has an actuating rod 15 formed integral therewith. A reduced portion 16 of the actuating rod 15 projects into and through an aperture 18 formed in the closure plug 12. A bushing 19 is threaded into the closure plug 12 and is provided to support and guide the reduced portion to of the actuating rod 15. A sealing bellows 20 is disposed on the reduced portion 16 and is welded or otherwise secured at one end to the actuating rod 15 and at the other end to the bushing 19 to provide a fluid tight seal therebetween.

An actuating bellows 21 is interposed between the piston 14 and the bushing w and is welded or otherwise secured in fluid tight relationship at its ends to the piston and bushing. The interior of the bellows Z1 is evacuated. A helical compression spring 22 is interposed between the piston 14- and the closure plug 12 and normally urges the piston 14 away from the closure plug 12 and towards the open end of the housing 10.

An internal partition is 2-4 is formed integral with the housing it and serves to separate the interior of the housing into chambers 25 and 26. A shaft 28 is threaded into the piston 14 on the side opposite the actuating rod 15 and projects through an aperturdZ? formed in the partition 24 and into the chamber 25. The aperture 2 is sized slightly larger than the diameter of the shaft 28 to define a restricted orifice interconnecting the chambers 25 and 26. A flexible diaphragm Bill is connected between the mounting flange l1 and a flange 31 formed integral with the shaft 2?; to define the exterior wall of the chamber 25. The chambers 25 and 26 are filed with a viscous fluid 32 which completely surrounds the piston 14, the bellows of the diaphragm 3% in sealing engagement with the flange 31. A porous membrane 355 is mounted within a central aperture in the cover 34 to provide a porous section which will admit sea water to the chamber 35 while precluding the entrance of sediment. The shaft 28 is also provided with a circumferential groove 39 to accommodate loclting wires it) positioned in apertures (shown in FIG. 2) in the cover 34- and which, until removed, lock the shaft 28 and hence the piston 14 in the positions shown in FIG. 1.

The closure plug 12 is provided with a recess 41 which accommodates an explosive fitting or detonator (not shown) of any suitable type. A second recess is provided in the closure plug 12 in axial alignment with the recess 41 and accommodates a booster charge 44 of tetryl or other suitable explosive material which, when ignited, serves to detonate the main charge (not shown) of the mine. An explosive lead 45 of tetryl or other suitable material is disposed in an aperture 46 formed in the reduced portion 16 of the actuating rod and serves to complete the explosive train from the detonator to the booster when axially aligned with these elements.

A switch 48 having contacts 49 is mounted on the inner end of the closure plug 12;. The inner end of the reduced portion 16 of the actuating rod carries a conductive member Sit which serves to complete an electrical circuit through the contacts 4% when brought into contact therewith.

Operation In order that a better understanding of the invention might be had, its mode of operation will now be described. Assuming that the device has been mounted in a mine and the appropriate electrical and mechanical connections have been made, the locking wires 40 are withdrawn from the groove 39 just before the mine is dropped into the water at the planting area. At this time, the various elements of the device are in the positions shown in FIG. 1 and neither the explosive train from detonator to booster nor the electrical circuit through the contacts 49 are completed.

As the mine sinks, sea water enters the chamber 35 through the porous membrane 33 and begins to exert a pressure corresponding to the water depth on the flexible diaphragm 3t). The ambient water pressure is transmitted through the viscous fluid 32 to the piston 14, which serves as one end of the bellows, and to the exterior surface of the bellows 21. Since the interior of the bellows 21 is evacuated, the bellows will start to contract as soon as the pressure exerted thereon exceeds the expanding pressure exerted by the compression spring 22 and thus start moving the piston 14 and actuating rod to the right as viewed in FIG. 1. The spring rate of the spring 22 is selected so that this condition prevails shortly after the mine moves below the surface of the water.

Since any tendency toward cavitation within the chamber 26 is precluded by the spring 22, the rate at which the bellows 21 contracts is determined by the rate at which the clearance volume surrounding the bellows can be filled with the fluid 32. Since the fluid 32 is of a viscous nature and the orifice defined by the shaft 23 and aperture 29 restricts the flow of fluid 32 from the chamber 25 into the chamber 26, the rate at which the bellows 21 contracts to move the actuating rod 15 will be relatively slow. The exact rate of contraction for any given depth of water will depend upon the specific viscosity of the viscous fluid utilized and the physical characteristics l of the restrictive orifice. A time of full contraction of approximately seconds was obtained with a test device using a silicone fluid with a specific viscosity of approximately 800 centistokes in eight feet of sea water with little more than working clearance between the shaft 28 and aperture 29.

The delay built into the operation of the device by utilization of a viscous fluid which must pass through a restricted orifice is for safety reasons. For obvious reasons, it would be highly undesirable to have an acoustic or magnetic mine armed too soon after it had been dropped over the fantail of a mine laying ship.

Since the pressure exerted by the ambient sea water is continuous, the bellows 21 will continue to contract until an O-ring seal 51 on the flange 31 engages the partition 24 at which time further motion is arrested and the parts have assumed the relative positions shown in PEG. 2. The seal 51 prevents the build up of any further pressure within the chamber 26 and thus permits the use of the device in deep water despite the fragile nature of the bellows Zl. In this position it will be noted that the lead 5 is axially aligned with the booster charge 44 to complete the explosive train, and the electrical circuit through the contacts 49 has been closed by the element 519 to complete the electrical arming circuits.

Since the present invention is intended primarily for the arming of mines which are to be laid in shallow water, provision must be made to preclude increases in internal mine pressure, due to temperature increases, from exerting a pressure on the arming device sufficient to overcome the ambient water pressure and disarm the mine. For example, the hydrostatic pressure available for arming a mine laid in eight to ten feet of water is only on the order of four or five pounds per square inch. Consequently, some provision must be made to minimize the effect of a rise in internal mine pressure on the arming device. The

ealing bellows 20 is provided to perform this function.

Since the housing 10, the closure plug 12 and the bushing 19 are tightly sealed together, the only point at which internal mine pressure is exerted on the actuating device is on the actuating rod 15 within sealing bellows 20. The actuating bellows 21 and sealing bellows 20 are so proportioned that the ratio of the effective area of the bellows 21 to the effective area of the bellows 20 is on the order of 1'2 to 1. This large ratio of effective areas reduces the effect of internal pressure changes to a negligible magnitude.

Thus it can be seen that the present invention provides a new and improved delayed action hydrostatically op- ,erated device possessing numerous features and advantages not found in prior art devices. The device of the present invention may be utilized to actuate explosive train arming devices and/ or electrical arming devices (such as those illustrated) as well as various other types of arming devices.

Obviously the present invention also has utility in various applications which require a delayed action device operated by fluid pressure in which the desired functions are completely different from the operation of arming a mine.

It is further obvious that, when the device of the present invention is used in an application which does not involve a problem analogous to applicants problem of compensating for variations in internal mine pressure, the sealing bellows 2t and its function could be eliminated.

It is to be understood that the above described embodiment is simply illustrative of the principal features of the present invention. Numerous other arrangements may be readily devised by those skilled in the art to achieve a similar device still'embodying the principles of the present invention and falling within the spirit and scope thereof.

What is claimed is:

l. A delayed-action, hydrostatically-operated arming device for shallow water mines comprising a housing having an open end and a substantially closed end, a piston slidably disposed within said housing, an actuating rod connected to one side of said piston and having one end thereof projecting through an aperture formed in the closed end of said housing, a first expansible bellows connected to and providing a fluid seal between said one side of said piston and the closed end of said housing, a second and smaller expansible bellows disposed within said first bellows connected to and providing a fluid seal between said actuating rod and the closed end of said housing, the space between said first and second bellows being evacuated, resilient means interposed between said piston and the closed end of said housing normally urging said piston toward the open end of said housing to initially expand said first and second bellows and retract said actuating rod, a shaft secured to the other side of said piston in axial alignment with said actuating rod and projecting toward the open end of said housing, a fiexible diaphragm connected in fluid sealing relationship between the open end of said housing and said shaft, a viscous fluid in said housing surrounding said piston and shaft and said first bellows, said viscous fluid being confined within said housing by said diaphragm, an internal partition formed integral with said hous nr and disposed between said piston and said diaphragm, said partition being provided with a central aperture encompassing said shaft to define a restricted orifice for retarding the flow of said viscous fluid from the chamber defined by said diaphragm and said partition to the chamber defined by said partition and the closed end of said housing, a protective cover secured to the open end of said housing in a position spaced from said diaphragm, said cover being provided with a porous section for enabling fluid access to the exterior of said diaphragm whereby fluid pressure applied to the exterior of said diaphragm causes said viscous fluid to flow through said orifice and compress and contract said first bellows against the urging of said resilient means and move said actuating rod, releasable means for locking said shaft to said cover to preclude premature operation of said device, and means on said shaft and engage able with said partition for limiting the extent of compression of said first bellows and the movement of said actuating rod.

2. A device as defined in claim ll including an explosive train having a first element mounted adjacent the exterior of the closed end of said housing and a second element mounted on said actuating rod, said first and second explosive elements being axially aligned to complete said explosive train only when said first bellows is contracted.

3. A hydrostatically actuated arming device for a shallow water mine comprising a casing, a bafiie member forming two chambers within said casing, a plunger reciprocally movable from an initial safe position to an armed position and slidably disposed within said baffie member, said bafile member having a small vent therein, a flexible diaphragm sealing one of said chambers and secured to said plunger, said diaphragm being exposed on one side thereof to the ambient sea water and movable by hydrostatic pressure thereagainst, a quantity of high viscosity silicone fiuid filling said chambers, a spring biased expansible bellows secured at one end thereof to said plunger for establishing a seal between said fluid and the interior of the mine, a second bellows of less cross sectional area than said spring biased bellows and arranged interiorly with respect thereto, said second bellows being disposed about said plunger in sealed relation to the spring biased bellows and having the interior thereof in communication with the interior of the mine, and arming means carried by said plunger for arming the mine as the plunger moves into the armed position.

2-. A delayed-action, hydrostatically-operated device comprising a housing having an open end and a closed end, an expansible bellows disposed Within said housing and having one end thereof connected in fluid sealing relationship to the closed end of said housing, the open end of said housing provides means for releasibly locking said bellows in an expanded position, an actuating rod partially disposed within said bellows and having one end secured to the free end of said bellows and the other end projecting through an aperture formed in the closed end of said housing, a high viscosity fluid filling said housing and surrounding said bellows, and a flexible member connected in fluid sealing relationship to the open end of said housing to confine said viscous fluid, the viscous fluid serving to transmit fluid pressure applied to the exterior of said flexible member to cause contraction of said bellows and consequent movement of said actuating rod.

5. A delayed-action, hydrostatically-operated device comprising a housing having an open end and a closed end, an expansible bellows disposed Within said housing and having one end thereof connected in fluid sealing relationship to the closed end of said housing, an actuating rod partially disposed within said bellows and having one end secured to the free end of said bellows and the other end projecting through an aperture formed in the closed end of said housing, a high viscosity fluid filling said housing and surrounding said bellows, and a flexible member connected in fluid sealing relationship to the open end of said housing to confine said viscous fluid, the viscous fiuid serving to transmit fluid pressure applied to the exterior of said flexible member to cause contraction of said bellows and consequent movement of said actuating rod, an explosive train having a first explosive element mounted on said housing and a second explosive element mounted on said actuating rod, said first and second ex plosive elements being axially aligned to complete said explosive train only when said bellows is fully contracted.

a. A delayed-action, hydrostatically-operated device comprising a housing having an open end and a closed end, an exnansible bellows disposed within said housing and having one end thereof connected in fluid sealing relationship to the closed end of said housing, an actuating rod partially disposed within said bellows and having one end secured to the free end of said bellows and the other end projecting through an aperture formed in the closed end of said housing, a high viscosity fiuid filling said housing and surrounding said bellows, and a fiexible member connected in fluid sealing relationship to the open end of said housing to confine said viscous fluid, the viscous fluid serving to transmit fluid pressure applied to the exterior or" said flexible member to cause contraction of said bellows consequent movement of said actuating rod, a switch having normally open contacts is mounted on said housing, and means are provided on said actuating rod for clos .id contacts only when said bellows is fully contracted.

'7. A delayed-action, hydrostatically-operated device comprising a housing having an open end and a substantially closed end, a piston slideably disposed within said housing, an actuating rod connected to said piston and projecting thro h an aperture formed in the closed end aid housing, an expansible bellows connected to and providing a fluid seal between said piston and the closed end of said housing, resilient means interposed between said piston and the closed end of said housing normally urging said piston toward the open end or said housing to expand said bellows, a high viscosity fluid filling said housing and surrounding said bellows, and a fiexible diaphragm connected to and providing a fiuid seal between said piston and the open end of said housing to confine said viscous fluid whereby fluid pressure applied to the exterior of sa d dia hragm is transmitted through said viscous fiuid to compress said bellows against the urging of said resilient means and move said actuating rod, said diaphragm is connected to said piston by means including a shaft secured to the side of said piston opposite said actuating rod and in axial alignment therewith, and an internal partition is formed integral with said housing and provided with a central aperture encompassing said shaft to define a restricted orifice for retarding the fiow of said viscous fluid.

A delayed-action, hydrostatically-operated device oneness '2? comprising a housing having an open end and a substantially closed end, a piston slideably disposed within said housing, an actuating rod connected to said piston and projecting through an aperture formed in the closed end of said housing, an expansible bellows connected to and providing a fluid seal between said piston and the closed end of said housing, resilient means interposed between said piston and the closed end of said housing normally urging said piston toward the open end of said housing to expand said bellows, a high viscosity fluid filling said housing and surrounding said bellows, a first element of an explosive train mounted on said housing, and a second element of said explosive train mounted on said actuating rod, said first and second explosive elements being axially aligned to complete said explosive train only when said bellows is contracted, and a flexible diaphragm connected to and providing a fluid seal between said piston and the open end of said housing to confine said viscous fluid whereby fluid pressure applied to the exterior of said diaphragm is transmitted through said viscous fluid to compress said bellows against the urging of said resilient means and move said actuating rod.

References Cited by the Examiner UNITED STATES PATENTS 1,652,941 12/27 isaac 73-410 2,466,071 4/49 Barnes et al 73-410 2,953,092 9/ 60 Walker 102-14 2,961,954 11/60 Moore et al. 102-16 3,015,271 1/62 MacAdams 102-14 FOREIGN PATENTS 726,105 2/32 France 102-14 BBIUl-slidlii A. BQRCHELT, Primary Examiner.

SAMUEL FEINBERG, SAMUEL BOYD, Examiners. 

4. A DELAYED-ACTION, HYDROSTATICALLY-OPERATED DEVICE COMPRISING A HOUSING HAVING AN OPEN END AND A CLOSED END, AN EXPANSIBLE BELLOWS DISPOSED WITHIN SAID HOUSING AND HAVING ONE END THEREOF CONNECTED IN FLUID SEALING RELATIONSHIP TO THE CLOSED END OF SAID HOUSING, THE OPEN END OF SAID HOUSING PROVIDES MEANS FOR RELEASIBLY LOCKING SAID BELLOWS IN AN EXPANDED POSITION, AN ACTUATING ROD PARTIALLY DISPOSED WITHIN SAID BELLOWS AND HAVING ONE END SECURED TO THE FREE END OF SAID BELLOWS AND THE OTHER END PROJECTING THROUGH AN APERTURE FORMED IN THE CLOSED END OF SAID HOUSING, A HIGH VISCOSITY FLUID FILLING SAID HOUSING 